[AusNOG] USB-powered switch +mirror

[Scott Howard]

On Tue, Jan 6, 2009 at 5:09 PM, Sean K. Finn <Sean.Finn at ozservers.com.au>wrote:

> What about one of those little DC-Powered Switches, perhaps a 5 or an 8
> port netgear that usually take 12v 500mA, or perhaps 5v 500mA ? Use a small
> step-up Transistor from Dick Smiths or Jaycar and bobs your uncle, USB 5V to
> 12V


Without some form of smarts you can't (well, shouldn't...) draw more than
100mA @ 5V from a single USB port. You can increase that up to 500mA per
port, but doing so requires the USB device to negotiate the higher draw, so
you need some USB smarts to do so, not just a straight power tap.

Just blindly trying to draw more than 100mA might work, but it can also
cause the computer//USB hub to shutdown the port completely.

  Scott.
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